”High-frequency traders are gaming the system, reaping billions in the process and undermining investor confidence in the fairness of the markets,” Bettinger said in a statement. “If confidence erodes further, the fuel of our free-enterprise system, capital formation, is at risk. We can’t allow that to happen.”

The comments mirror ones Schwab made in an opinion article last year.

Bettinger said Schwab believes investing in equities remains a “primary path” to long-term wealth creation as well as in the “long-term structural integrity” of the markets to help individual investors.

Bettinger said Schwab executives “applaud” recently-announced efforts by New York Attorney General Eric Schneiderman to probe high-frequency trading. He also said Schwab encourages the Securities and Exchange Commission to “raise the urgency on the issue and do all they can to stop this infection in our capital markets.”

Schwab also pushed back against claims by high-frequency trading defenders that these sophisticated market players help retail investors by adding liquidity and lowering the cost of executing trades.

“High-frequency trading isn’t providing more efficient, liquid markets; it is a technological arms race designed to pick the pockets of legitimate market participants,” Bettinger said.

Bettinger said he believes exchanges have tilted the playing field away from investors by allowing growing numbers of complex order types and providing unequal access to information.

Lewis told FOX Business’s Maria Bartiromo on Thursday the system that allows high-frequency traders to skim off fractions of pennies from each trade “is incredibly complicated so nobody understands it and is incredibly unstable.” Lewis is promoting a new book on the topic called Flash Boys.

Larry Summers recently told FOX News it's a "staggering exaggeration to say that the market is rigged," though the former U.S. Treasury secretary did concede reforms are "overdue."